Air compressors

ABSTRACT

In an air compressor system for supplying compressed air to a receiving tank and being operated by an internal combustion engine including a carburetor; a control is provided for operating the carburetor throttle between idle and full speed positions in response to the pressure in the air receiving tank. The carburetor control includes a reciprocable pneumatic motor supplied with air from the receiving tank through a pilot valve. Additionally, the pilot valve controls the flow of air from the receiving tank to the air compression cylinders for purposes of unloading the latter at the same time the carburetor is moved to idle position when the air in the receiving tank reaches a predetermined amount. Air for unloading the compression cylinders is sequentially fed into the compression cylinders so that the load on the engine is gradual during loading and unloading of the compression cylinders. The air intake manifold for supplying the compression cylinders with air to be compressed is also connected to the carburetor to divert air to the carburetor to reduce the temperature of the air passing through the air compression cylinders during unloading and thereby reduce the temperature of the compressor valves during this stage. In one modification, the control system is further provided with a thermostatic valve which senses the temperature of the cooling water in the engine to detain the air compressing operation until the engine has become sufficiently warm as sensed by the temperature of the cooling water in the engine.

United States Patent [191 Ostwald [451 Apr. 23, 1974 [54] AIRCOMPRESSORS [75] Inventor: Richard Ostwald, Bowling Green,

[73] Assignee: Gordon Smith & Co., Inc., Bowling Green, Ky.

22 Filed: Jul 5, 1972 [21] Appl. No.: 268,943

[52] US. Cl 417/12, 417/27, 417/34 [51] Int. Cl. F04b 49/00 [58] Fieldof Search 417/34, 27, 32, 28, 298,

[56] References Cited 1 UNITED STATES PATENTS 11/1928 Holdsworth 417/284/1930 Saharoff Primary Examiner-William L. Freeh Attorney, Agent, orFirm-Browne, Beveridge,' De Grandi & Kline [57 ABSTRACT In an aircompressor system for supplying compressed air to a receiving tank andbeing operated by an internal combustion engine including a carburetor;a control is provided for operating the carburetor throttle between idleand full speed positions in response to the pressure in the airreceiving tank. The carburetor control includes a reciprocable pneumaticmotor supplied with air from the receiving tank through a pilot valve.Additionally, the pilot valve controls the flow of air from thereceiving tank to the air compression cylinders for purposes ofunloading the latter at the same time the carburetor is moved to idleposition when the air in the receiving tank reaches a predeterminedamount. Air for unloading the compression cylinders is sequentially fedinto the compression cylinders so that the load on the engine is gradualduring loading and unloading of the compression cylinders. The airintake manifold for supplying the compression cylinders with air to becompressed is also connected to the carburetor to divert air to thecarburetor to reduce the temperature of the air 'passing through the aircompression cylinders during unloading and thereby reduce thetemperature of the compressor. valves during this stage; In onemodification, the control system is further provided with a thermostaticvalve which senses the temperature of the cooling water in the engine todetain the air compressing operation until the engine has becomesufficiently warm as sensed by the temperature of the cooling water inthe engine.

11 Claims, 4 Drawing Figures 1 ?ATENTE[]APR23I974 SHEET1UF3 AIR FILTER.

0 G C) 3 G AIR REC EIVING TANK.

PATENTEBAPR 23 1974 3806 279 sum 2 UF 3 FIG. 2

FIG. 3

Ram-mm 23 1974 1806; 279

SHEET 3 OF 3 FIG. 4

AIR COMPRESSORS OBJECTS OF INVENTION The present invention generallyrelates to a gas compressing system and more specifically to a novel andimproved system and method for controlling a gas compressor such as anair compressor particularly of the type driven by an internal combustionengine. The present invention also relates to a novel carburetor controland linkage.

One of the objects of the present invention is to provide a novel andimproved control system for controlling the operation of a gascompressor such as an air compressor. Included herein is the provisionof such a control system which is particularly suitable for aircompressors driven by an internal combustion engine.

A further object of the present invention is to provide such a controlsystem which will control the operation of a gas compressor in responseto pressure in the receiving tank which is supplied with compressed gasby the compressor. Included herein is the provision of such a controlsystem which eliminates conventional control systems and those of theprior art which operate in response to the speed of the engine thatdrives the compressor.

Another object of the present invention is to provide such a controlsystem which gradually loads and unloads the gas compression cylindersof the compressor to reduce load and wear on the associated engine.

Yet another object of the present invention is to providesuch a controlsystem for a gas compressor which will permit operation of the gascompressor only after the associated engine reaches a predetermined warmtemperature.

A still further object of the present invention is to provide a novelcontrol for a carburetor including a novel linkage for operating thethrottle lever of the carburetor, which control and linkage may beconnected to a source of compressed air or other gas to operate thecarburetor in response to gas pressure. Included herein is the provisionof such a control and linkage which reduces wear on the carburetorthrottle shaft while further reducing shocks imparted thereto when movedbetween idle and full speed positions. Further included herein is theprovision of such a carburetor control and linkage which may besubstituted in a conventional carburetor system employed withconventional air compressors.

SUMMARY OF THE INVENTION The above and other objects are achieved in anair compressor system such as may include a block containing a pluralityof air compression cylinders with conventional valves for controllingthe supply and exhaust of air into and from the cylinders andconventional reciprocating pistons for compressing air in the cylinders.Additionally, the block contains a plurality of internal combustioncylinders equipped with reciprocating pistons for driving a crank shaftwhich in turn drives the air compression pistons in conventional manner.Air compressed in the air compression cylinders is fed to an airreceiving tank which is equipped with an outlet nozzle for connection toa pneumatic device to power the same.

In accordance with the present invention, the carburetor for theinternal combustion engine is operated in response to the pressure inthe air receiving tank so that when the air in the latter reaches apredetermined pressure for example 100 psi, the carburetor will be movedto an idle speed position simultaneously with opening of the valves inthe air compression cylinders to unload the same. This is achieved byconnecting a reciprocable fluid motor such as an air cylinder to thelever mounted on the carburetor throttle shaft to rotate the same uponactuation of the fluid motor in response to air pressure from the airreceiving tank. The fluid motor is provided with a return spring so thatwhen the air pressure in the receiving tank falls to a predeterminedamount for example psi, the return spring will cause the throttle leverof the carburetor to rotate in the opposite direction into the fullspeed position at which time the air compressing operation will resumein the compression cylinders to restore the pressure in the airreceiving tank.

The fluid motor is supplied with and exhausted of air through means of apilot valve connected to the air receiving tank. The pilot valve also isconnected to unloading pistons associated with the air compressioncylinders to control the loading and unloading thereof. Thus when thepressure in the air receiving tank reaches a predetermined amount suchas psi, the pilot valve will open and admit air to the fluid motor tomove the carburetor to the idle position while simultaneously providingair to the unloading pistons of the air compressioncylinders to open thevalves therein and vent the cylinders to atmosphere and to therebyunload the same and cease the compression of air.

Upon use of the compressed air from the receiving tank the pressuretherein will of course drop, and when the pressure drops to apredetermined value say 85 psi the pilot valve will move to anotherposition closing communication with the tank while venting the fluidmotor and the unloading pistons to atmosphere whereupon the carburetorwill move to the full speed position and air compression will resume inthe air compression cylinders. To reduce the load on the engine, theunloading pistons are connected in series by one line to the pilot valveso that the compression cylinders are sequentially gradually loadedand'unlloaded.

The carburetor control is further provided with adjustable safety stopsfor determining the idling and full speed positions thereof of thecarburetor. Additionallythe stop which governs the idling speed isprovided with a rubber bumper to absorb shocks when the carburetorthrottle lever is moved to the idling position.

When the carburetor is in the idle position and the compressioncylinders are unloaded and air is moving through the compressioncylinders to atmosphere, the temperature of the air passing through thecylinders will increase the temperature of the valves in the aircompression cylinders. This increased temperature if unchecked may causedamage to the valves. To overcome the latter, an air line is connectedbetween the air intake manifold and the carburetor to divert some of theair away from the compression cylinders to the carburetor.

The system may be modified to add a thermostatic control valve whichsenses the temperature of the water in the cooling system of the engineand detains the air compressing operation until the temperature of thecooling water reached a predetermined amount such as 140 F.

DRAWINGS Other objects and advantages of the present invention willbecome apparent from the following more detailed description of thedrawings in which:

FIG. 1 is a schematic view of an air compressor systern embodying thepresent invention;

FIG. 2 is an elevational view of a carburetor control system included inthe system of FIG. 1;

FIG. 3 is a plan view of a linkage which is a part of the carburetorcontrol system of FIG. 2; and

FIG. 4 is a view similar to FIG. 1 but illustrating a modified systemfurther in accordance with the present invention.

DETAILED DESCRIPTION tional reciprocating pistons and compressor valves(not shown) such as of the type shown in the aforemen tioned U.S. Pat.No. 1,992,400 and therefore need not be described in any detail.Additionally theair compression cylinders 12 and their associated partsmay conform to that disclosed in U.S. Pat. application Ser. No. 256,604filed May 24, 1972 entitled SEAL AS- SEMBLY FOR AIR COMPRESSOR VALVE,assigned to Gordon Smith & Co., Inc., the assignee of the subjectapplication and whose disclosure is hereby incorporated by referenceherein. These parts also may conform to those included in the model 90air compressor manufactured by Gordon Smith & Co., Inc. of Bowling GreenKentucky, the assignee of the subject application. The internalcombustion cylinders 14 may also be any suitable conventional or othertype such as may conform to that disclosed in the aforementioned U.S.Pat. No. 1,992,400 or incorporated in the model 90 air compressormanufactured by Gordon Smith & Co., Inc. The same applies with respectto other parts of the engine such as the battery and ignition system andcooling system etc. which although not shown may be conventional and arewell known and therefore need no further description.

Returning now to FIG. 1, air is supplied to an air intake manifold 16through an air filter 18 where it is led for example through theschematically illustrated lines 20 to the compression cylinders 12 to becompressed therein and later discharged to an air receiving tank 22through an air discharge manifold 24 connected to air compressioncylinders 12 such as schematically illustrated by lines 26. Fuel forcombustion cylinders 14 is provided from a fuel tank (not shown) througha carburetor 30 having a carburetor or throttle shaft 32 on which isfixed a throttle lever 34 for purposes of rotatably oscillating thecarburetor shaft 32. The carburetor is further shown as provided with aconventional choke shaft 36 connected to a choke cable 38 which form nopart of the present invention. It should further be understood that theinternal parts of the carburetor not shown also form no part of thepresent invention as they may be conventional or otherwise insofar asthe disclosure of the present invention is concerned.

When throttle lever 34 is in one position indicated by the line 40 inFIG. 2 the carburetor will be in the idle speed position which is usedwhen the compression cylinders 12 are in an unloading mode during whichtime air is being brought into the air compression cylinders 12 throughlines 20 and discharged therefrom to atmosphere with no air compressiontaking place. In the opposite position of throttle lever 34 shown byline 42, the carburetor will be in the full speed position which isemployed to operate the pistons in the air compression cylinders 12 atthe desired speed for compressing air. In this condition, the valves inair compression cylinders 12 will be loaded and the air compressionoperation will take place to provide compressed air to air receivingtank 22 via air discharge manifold 24. During this air compression mode,the valves associated with the air compression cylinders 12 areoperating to emit air into the air compression cylinders for compressionand to discharge compressed air into discharge manifold 24. When thepressure in the air receiving tank 22 reaches a certain predeterminedamount such as I00 psi, the valves associated with air compressioncylinders 12 are unloaded so that air fed into compression cylinders 12through lines 20 is not compressed but rather is vented to atmosphere.This occurs during the idling position of the carburetor. Movement ofthe air compressor valves for unloading air compression cylinders 12 isachieved through an unloading piston associated witheach of the aircompression cylinders, the

unloading pistons not being schematically shown at 25. The'unloadingpistons are operated in response to fluid pressure preferably airpressure in accordance withv the present invention as will be describedbelow in greater detail. For a further detailed disclosure of the aircompressor valves and the unloading pistons, reference may be made tothe aforementioned copending U.S. Pat. application Ser. No. 256,604filed May 24, 1972 entitled SEAL ASSEMBLY FOR AIR COMPRESSOR VALVE. Itshould be understood however that any other type of fluid operatedunloading piston may be employed in carrying out the present invention.

In accordance with the present invention, the throttle lever 34 of thecarburetor is moved between idle and full speed positions in response tothe pressure in air receiving tank 22. In the. shown embodiment, this isachieved by providing a fluid motor which may be a pneumatic motor 50 inthe form of an air cylinder having a piston therein operated by airsupplied from air receiving tank 22. Air cylinder 50 may be mounted inany suitable manner relative to the block 10 such as by the generallyU-shaped bracket 52 which may be made from rigid material such as asuitable steel or alloy material. Referring to FIG. 2 bracket 52includes two spaced upstanding arms 54 and 56 both having aperturestherein; one receiving an adjustable stop in the form of a stud 58having threads thereon received in complimentary threads in arm 56 andfurther including a lock nut 60 threaded on stud 58. The aperture in theother arm 54 is threaded to receive one end of air cylinder 50 and alock nut 62 is provided therein to secure the air cylinder to arm 54.The piston shaft of pneumatic cylinder 50 is connected to an elongatedrod 64 having threads on one end at 66 for receipt in a hexagonalcoupling 68. The other end of coupling 68 has a ball and socket jointincluding a ball member 70 having a hexagonal portion 72 and a threadedstud portion 74 which is received in a sleeve 76 with a lock nut 78received on the stud portion 74. As shown in FIG. 3, sleeve 76 isrecessed at one side at the other end thereof and is connected tothrottle lever 34 by means of a threaded stud 80 which passes through anaperture in throttle lever 34 and is secured relative thereto by locknuts 82 and 84. Stud 80 is connected to sleeve 76 by a ball-socket jointat 86.

It will be seen that upon reciprocation of the piston of 'air cylinder50 the motion will be transmitted to throttle lever 34 by sleeve 76 tooscillate throttle shaft 32. Movement of the linkage assembly 64, 68, 76to the right as viewed in FIG. 2 will place the carburetor shaft 32 inposition for idling, whereas movement to the left will place thecarburetor shaft 32 in position for full speed operation. The idlingposition is determined by engagement of the forward end of sleeve 76against stop 58 which will lessen the shock and wear on throttle shaft32. TO further reduce shock a rubber or other resilient bumper 90 isplaced over the extremity of stop 58 as shown in FIG. 2. To adjust theidling position of the throttle lever 34, lock nut 60 in stop 58 isloosened away from bracket arm 56 and stud 58 is rotated to move ittowards or away from sleeve 76 depending on whether the idling speed isdesired to be increased or decreased.

The full speed position of the throttle shaft 32 is determined bythedistance between the stud 80 and rod 64. By loosening lock nut 78,hexagonal portion 72 may be grasped by a tool and rotated to advance orretract stud portion 74 out of or into sleeve 76 to adjust the fullspeed of the carburetor. In addition a safety stop 94 is provided in theform of a screw mounted in the base of throttle lever 34 as shown inFIG. 2. A coil compression spring is provided between the head of screw94 and the lever 34 to secure the screw against movement. At the base ofthe carburetor a pin (not shown) is provided in fixed position to engagescrew 94 when the lever moves into the full speed position. This insuresthat the lever 34 cannot be moved beyond a certain full speed set by theoperator. Movement of the linkage to the left as viewed in FIG. 2 toplace the carburetor in the full speed mode is obtained by a returnspring 98 in air cylinder 50 when the latter is exhausted of air as willbe described below.

Referring to FIG. 1, air is fed to the pneumatic cylinder 50 to operatethe same for moving the carburetor throttle lever 34 to the idlingposition through a pilot valve 100 connected to receive air fromreceiving tank 22 by line 102. The outlet 104 of the pilot valve isconnected to T joint 106 for supplying air to pneumatic cylinder 50 vialine 108 and also for supplying air to the unloading pistons of the aircompression cylinders 12 through line 110. In accordance with anotheraspect of the present invention, the unloading pistons of the aircompression cylinders receive their air from line 110 sequentially andgradually through lines 114, 116 and 1 18 so that the air compressioncylinders 12 are gradually loaded and unloaded to reduce load on theengine. Lines 114, 116 and 118 may consist of one-eighth inch diametertubing. Air passing to the unloading pistons of the air compressioncylinders will first pass through the cylinder 12 shown in the lefthandside of FIG. 1 and then to the next adjacent cylinder and then to thenext adjacent cylinder and then finally to the cylinder on the righthand side of FIG. 1. The unloading cylinderswill also be sequentiallyand gradually exhausted to atmosphere through the vent 120 of the pilotvalve.

Pilot valve itself may have any suitable conventional constructionincluding a condition responsive ball check valve 122 which will openwhen the pressure in air receiving tank 22 reaches a certain value suchas 100 psi to permit air to flow from the air receiving tank throughline 102 to pneumatic cylinder 50 through line 108 and simultaneously tothe unloading pistons of the air compression cylinders through lines and114, l 16 and 118. This will have the effect of moving carburetorthrottle 34 to the idling position while causing the air compressioncylinders 12 to unload whereby air fed into the air compressioncylinders through lines 20 is vented to atmosphere and no compressiontakes place.

When the air in receiving tank 22 is used to operate a device by openingvalve the pressure in air receiving tank 22 falls to a certain valuesuch as 85 psi, the check valve 122 in pilot valve 100 will close andthe air vent 120 will be placed into communication with lines 108 and110 whereby the air in pneumatic cylinder 50 and the unloading pistonswill be vented to atmosphere through pilot valve 100 and vent 120. Thespring 98 associated with pneumatic cylinder 50 will then cause thepneumatic cylinder piston shaft to move to the left (as viewed inFIG. 1) thereby causing carburetor throttle lever 34 to pivotcounterclockwise into the full speed position wherein the aircompression operation in the air compression cylinders 12 will resumeand compressed air will be supplied to air receiving tank 22 through airdischarge manifold 24.

As noted above, during the unloading cycle of the air compressioncylinders 12, air is being fed from the air intake manifold 16 throughlines 20 to compression cylinders 12 which can cause the temperature ofthe compressor valves associated with the air compression cylinders toincrease to an unsafe degree causing damage to the air compressorvalves. To reduce the temperature of the valves, a conduit 132 is placedbetween the air intake manifold 16 and carburetor 30 to supply thecarburetor with a portion of the air from intake manifold 16. This willlessen the amount of hot air fed through the air compression cylinders12 to thereby re duce the temperature of the compressor valves.

The control system of the present invention may be modified to add athermostatic control valve to detain the air compressing operation untilthe temperature of the cooling water in the internal combustion enginehas reached a desired degree for example F. Referring to FIG. 4 athermostatic control valve 140 may be mounted on the block or on theradiator 142 to sense the temperature of the cooling water 144in theengine system.

Thermostatic control valve 140 may be any suitable or conventional typereadily obtainable on the market such as includes two inlet ports 152and 156 which may be alternatively placed in communication with anoutlet port 146 by means of a spool valve member 143 having a pluralityof spools for controlling registration between ports 152, 156 and 146.Valve 140 further includes a temperature sensing element 139 in contactwith the cooling water 144 in the engine system so as to actuate thespool member 143 in response to the temperature of the cooling water144. Port 152 is placed in communication with the air in receiving tank22 by means of line 154 while port 156 is adapted to be placed intocommunication with receiving tank 22 through means of pilot valve 100which is the same as that disclosed in FIG. 1 and described above.Outlet port 146 of valve is connected to unloading pistons 25 of aircompression cylinders 12 by means of line 148, and connected to aircylinder 50 controlling the carburetor by means of line 150.

Upon initial starting of the engine, the cooling water 144 will be lessthan 140 F and the spool valve member 143 will be in position to opencommunication between ports 152 and 146. Air will thus be fed fromreceiving tank 22 through line 154 port 152, port 146 and line 148 tosend air to the unloader pistons 25 associated with the air compressioncylinders. However the pressure in receiving tank 22 at this time willnot be sufficien't to cause the unloading pistons 25 to move into anunloading position. Thus air compression in air cylinders 12 begins totake place at this initial phase. At this time pilot valve 100 will beclosed since the pressure in air receiving tank will be less than thatrequired to open up the ball check valve in pilot valve 100.

When the pressure in air receiving tank reaches a predetermined amountfor example 40 psi this wil be sufficient to actuate unloading pistons25 associated with the air compression cylinders 12 and also to actuatefluid motor 50 to the right as viewed in FIG. 4 to place the carburetorin idling position. Thus no further air compression will take place incylinders 12 as is desired since the engine at this time is notsufficiently warm. The engine will continue to idle with the compressionvalves unloaded until the temperature of the cooling water 144 of theengine reaches a predetermined amount l40 F as sensed by sensing element139. When this occur spool valve member 143 will be moved to closecommunication between ports 152 and port 146 and open communicationbetween ports 146 and 156. At this point check valve 122 of pilot valve100 will be in closed position such that pilot valve 100 will vent airfrom the thermostatic valve 140 to atmosphere through vent port 120.This will cause return spring 98 in fluid motor 50 to move thecarburetor to full speed position while also permitting air compressionto take place in cylinders 12. From this point on and as long as thetemperature of the cooling water 144 of the engine remains at 140 F orabove, the thermostatic control valve 140 will remain in positionwherein line 158 is open to communication with lines 148 and 150. Whenthe pressure in the receiving tank reaches.

the predetermined value for example 100 psi, the ball check valve inpilot valve 100 will open permitting air from receiving tank 22 to beconveyed through line 158 and lines 148 and 150 to unload the aircompression cylinders 25 and to move the carburetor to the idlingposition as described above.

I claim:

1. In a gas compressor system including gas compressor means forcompressing a gas such as air, a gas receiving chamber supplied withcompressed gas from said compressor means, said compressor meansincluding unloading means for preventing compression of gas, drive meansincluding an internal combustion engine for driving said gas compressormeans, and control means for moving said drive means to an idlingposition wherein it operates at a certain low speed and for moving saidunloading means to prevent gas compression in response to a firstpredetermined pressure in said receiving tank, said control meansfurther including means for moving said drive means to a full speedposition and for simultaneously restoring said unloading means to permitcompression of gas by said compressor means in response to a secondpredetermined pressure in said receiving tank lower than said firstpredetermined pressure, and wherein there is further includedtemperature control means responsive to the temperature of said internalcombustion engine for preventing gas compression until the temperatureof said internal combustion engine has reached a predetermined degreeupon start up of the engine and regardless of the pressure in saidreceiving tank.

2. The system defined in claim 1 wherein said drive means includes acarburetor and a fluid actuated motor for operating the carburetor inresponse to pressure in said receiving tank, and wherein said firstcontrol means includes valve means for controlling the flow between saidreceiving tank and said fluid actuated motor, and wherein saidtemperature control means includes a second valve means and atemperature sensing element in heat transfer relation with said enginefor operating the second valve means in response to temperature of theengine, said second valve means controlling fluid flow between thepressure receiving tank and the fluid actuator motor and unloadingmeans.

3. In a gas compressor system including gas compressor means forcompressing a gas such as air, a gas receiving chamber supplied withcompressed gas from said compressor means, said compressor meansincluding unloading means for preventing compression of gas, drive meansfor driving said gas compressor means, and control means for moving saiddrive means to an idling position wherein it operates at a certain lowspeed and for moving said unloading means to prevent gas compression inresponse to a first predetermined pressure in said receiving tank, andwherein said control means further includes means for moving said drivemeans to a full speed position and for simultaneously restoring saidunloading means to permit compression of gas by said compressor means inresponse to a second predetermined pressure in said receiving tank lowerthan said first predetermined pressure, and wherein said drive meansincludes an internal combustion engine including a carburetor having athrottle shaft for moving the carburetor between idling and full speedpositions, said control means being operatively connected to saidthrottle shaft to operate the same between idling and full speedpositions in response to pressure in said receiving tank, and whereinsaid gas compressor means is an air compressor having an air inletmanifold for supplying said air compressor cylinders with air, saidmanifold being connected to said carburetor for diverting some of theair away from the air compressor cylinders to reduce temperature in saidcylinders.

4. In combination with a carburetor for an internal combustion engine,the carburetor including a rotatable throttle shaft for operating thecarburetor and a throttle lever fixedto said shaft to rotate the sameupon pivotal movement of the lever; means for actuating and controllingthe lever comprising, a fluid motor, interconnecting means including areciprocable rod interconnecting said fluid motor and said lever topivot the lever, a fixed support, a stop movably mounted on said fixedsupport for movement towards or away from said rod to adjust thedistance between said .rod and said stop, said stop being engageable bysaid rod to limit movement of said rod in one direction, and whereinthere is further included resilient means on said stop for absorbingshocks from said rod.

5. A combination defined in claim 4 wherein there is further includedsecond stop means engageable with portions of the lever to limitmovement of the lever in the opposite direction.

6. The combination defined in claim 4 wherein said lever is located onone side of said rod and there is fur ther included a pininterconnecting said lever adjacent the free end thereof and one side ofsaid rod.

7. The combination defined in claim 4 wherein said resilient means is abumper on the stop engageable with said rod.

8. A combination defined in claim 4 wherein said fluid motor has anactuating stern and wherein there is further included adjustablecoupling means interconnecting said actuating stern and said rod andbeing adjustable to vary the distance between the rod and the fluidmotor.

9. A combination defined in claim 8 wherein said stop has a plurality ofthreads and wherein said fixed support has a threaded passage receivingsaid stop with the threads interengaged for adjusting said stop relativeto the fixed support.

10. The combination defined in claim 4 further including aninternational combustion engine supplied with fuel by said carburetor,an air compressor driven by said engine, an air receiving tank suppliedwith compressed air by said air compressor, said fluid motor beingconnected to said air receiving tank to be operated by air therefromwhen the pressure in said tank reaches a predetermined value to move thecarburetor shaft into an idling position for operating the engine at anidling speed.

11. The combination defined in claim 10 further in-' secondpredetermined value lower than said first value. =l l

1. In a gas compressor system including gas compressor means forcompressing a gas such as air, a gas receiving chamber supplied withcompressed gas from said compressor means, said compressor meansincluding unloading means for preventing compression of gas, drive meansincluding an internal combustion engine for driving said gas compressormeans, and control means for moving said drive means to an idlingposition wherein it operates at a certain low speed and for moving saidunloading means to prevent gas compression in response to a firstpredetermined pressure in said receiving tank, said control meansfurther including means for moving said drive means to a full speedposition and for simultaneously restoring said unloading means to permitcompression of gas by said compressor means in response to a secondpredetermined pressure in said receiving tank lower than said firstpredetermined pressure, and wherein there is further includedtemperature control means responsive to the temperature of said internalcombustion engine for preventing gas compression until the temperatureof said internal combustion engine has reached a predetermined degreeupon start up of the engine and regardless of the pressure in saidreceiving tank.
 2. The system defined in claim 1 wherein said drivemeans includes a carburetor and a fluid actuated motor for operating thecarburetor in response to pressure in said receiving tank, and whereinsaid first control means includes valve means for controlling the flowbetween said receiving tank and said fluid actuated motor, and whereinsaid temperature control means includes a second valve means and atemperature sensing element in heat transfer relation with said enginefor operating the second valve means in response to temperature of theengine, said second valve means controlling fluid flow between thepressure receiving tank and the fluid actuator motor and unloadingmeans.
 3. In a gas compressor system including gas compressor means forcompressing a gas such as air, a gas receiving chamber supplied withcompressed gas from said compressor means, said compressor meansincluding unloading means for preventing compression of gas, drive meansfor driving said gas compressor means, and control means for moving saiddrive means to an idling position wherein it operates at a certain lowspeed and for moving said unloading means to prevent gas compression inresponse to a first predetermined pressure in said receiving tank, andwherein said control means further includes means for moving said drivemeans to a full speed position and for simultaneously restoring saidunloading means to permit compression of gas by said compressor means inresponse to a second predetermined pressure in said receiving tank lowerthan said first predetermined pressure, and wherein said drive meansincludes an internal combustion engine including a carburetor having athrottle shaft for moving the carburetor between idling and full speedpositions, said control means being operatively connected to saidthrottle shaft to operate the same between idling and full speedpositions in response to pressure in said receiving tank, and whereinsaid gas compressor means is an air compressor having an air inletmanifold for supplying said air compressor cylinders with air, saidmanifold being connected to said carburetor for diverting some of theair away from the air compressor cylinders to reduce temperature in saidcylinders.
 4. In combination with a carburetor for an internalcombustion engine, the carburetor including a rotatable throttle shaftfor operating the carburetor and a throttle lever fixed to said shaft torotate the same upon pivotal movement of the lever; means for actuatingand controlling the lever comprising, a fluid motor, interconnectingmeans including a reciprocable rod interconnecting said fluid motor andsaid lever to pivot the lever, a fixed support, a stop movably mountedon said fixed support for movement towards or away from said rod toadjust the distance between said rod and said stop, said stop beingengageable by said rod to limit movement of said rod in one direction,and wherein there is further included resilient means on said stop forabsorbing shocks from said rod.
 5. A combination defined in claim 4wherein there is further included second stop means engageable withportions of the lever to limit movement of the lever in the oppositedirection.
 6. The combination defined in claim 4 wherein said lever islocated on one side of said rod and there is further included a pininterconnecting said lever adjacent the free end thereof and one side ofsaid rod.
 7. The combination defined in claim 4 wherein said resilientmeans is a bumper on the stop engageable with said rod.
 8. A combinationdefined in claim 4 wherein said fluid motor has an actuating stem andwherein there is further included adjustable coupling meansinterconnecting said actuating stem and said rod and being adjustable tovary the distance between the rod and the fluid motor.
 9. A combinationdefined in claim 8 wherein said stop has a plurality of threads andwherein said fixed support has a threaded passage receiving said stopwith the threads interengaged for adjusting said stop relative to thefixed support.
 10. The combination defined in claim 4 further includingan international combustion engine supplied with fuel by saidcarburetor, an air compressor driven by said engine, an air receivingtank supplied with compressed air by said air compressor, said fluidmotor being connected to said air receiving tank to be operated by airtherefrom when the pressure in said tank reaches a predetermined valueto move the carburetor shaft into an idling position for operating theengine at an idling speed.
 11. The combination defined in claim 10further including spring means for moving said fluid actuator motor andsaid rod in an opposite direction for moving the throttle into a fullspeed position for compressing air when the pressure in said receivingtank reaches a second predetermined value lower than said first value.